Design of 3-dimensional metal oxide nanofibers by electrospinning is
being widely explored. However, the impacts of calcination and sintering
on the resulting morphology remain unknown. For the first time, (La0.6Sr0.4)0.99CoO3-δ(LSC) nanofiber, which is among the most promising electrode materials
for solid oxide fuel cells, was synthesized by sol-gel electrospinning.
By elevating the temperature in oxygen using in situ transmission
electron microscopy, we discovered the structural transitions from
nanofibers to nanotubes and then to nano-pearl strings. This facile and
up-scalable method can be widely applied to design metal oxide
one-dimensional nanomaterials with precise control in both geometry
(nanofiber, nanotube and nano-pearl string) and surface area (by varying
grain size).